On Fri, Mar 13, 2026 at 8:08 AM Eugenio Perez Martin <[email protected]> wrote: > > On Fri, Mar 13, 2026 at 7:05 AM Jason Wang <[email protected]> wrote: > > > > On Thu, Mar 12, 2026 at 2:24 PM Eugenio Perez Martin > > <[email protected]> wrote: > > > > > > On Thu, Mar 12, 2026 at 4:58 AM Jason Wang <[email protected]> wrote: > > > > > > > > On Wed, Mar 11, 2026 at 3:08 AM Eugenio Pérez <[email protected]> > > > > wrote: > > > > > > > > > > Add the VDUSE_F_QUEUE_READY feature flag. This allows the kernel > > > > > module > > > > > to explicitly signal userspace when a specific virtqueue has been > > > > > enabled. > > > > > > > > > > In scenarios like Live Migration of VirtIO net devices, the dataplane > > > > > starts after the control virtqueue allowing QEMU to apply > > > > > configuration > > > > > in the destination device. > > > > > > > > > > Signed-off-by: Eugenio Pérez <[email protected]> > > > > > --- > > > > > v2: > > > > > * Fix comment of vduse_dev_request.vq_ready > > > > > * Set vq_ready before sending the message to the VDUSE userland > > > > > instance, avoiding the need for SMP sync after receiving the > > > > > message. > > > > > --- > > > > > drivers/vdpa/vdpa_user/vduse_dev.c | 28 +++++++++++++++++++++++++++- > > > > > include/uapi/linux/vduse.h | 18 ++++++++++++++++++ > > > > > 2 files changed, 45 insertions(+), 1 deletion(-) > > > > > > > > > > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c > > > > > b/drivers/vdpa/vdpa_user/vduse_dev.c > > > > > index 17e0358d3a68..4f642b95a7cb 100644 > > > > > --- a/drivers/vdpa/vdpa_user/vduse_dev.c > > > > > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c > > > > > @@ -9,6 +9,7 @@ > > > > > */ > > > > > > > > > > #include "linux/virtio_net.h" > > > > > +#include <linux/bits.h> > > > > > #include <linux/cleanup.h> > > > > > #include <linux/init.h> > > > > > #include <linux/module.h> > > > > > @@ -53,7 +54,7 @@ > > > > > #define IRQ_UNBOUND -1 > > > > > > > > > > /* Supported VDUSE features */ > > > > > -static const uint64_t vduse_features; > > > > > +static const uint64_t vduse_features = BIT_U64(VDUSE_F_QUEUE_READY); > > > > > > > > > > /* > > > > > * VDUSE instance have not asked the vduse API version, so assume 0. > > > > > @@ -120,6 +121,7 @@ struct vduse_dev { > > > > > char *name; > > > > > struct mutex lock; > > > > > spinlock_t msg_lock; > > > > > + u64 vduse_features; > > > > > u64 msg_unique; > > > > > u32 msg_timeout; > > > > > wait_queue_head_t waitq; > > > > > @@ -601,8 +603,29 @@ static void vduse_vdpa_set_vq_ready(struct > > > > > vdpa_device *vdpa, > > > > > { > > > > > struct vduse_dev *dev = vdpa_to_vduse(vdpa); > > > > > struct vduse_virtqueue *vq = dev->vqs[idx]; > > > > > + struct vduse_dev_msg msg = { 0 }; > > > > > + int r; > > > > > > > > > > vq->ready = ready; > > > > > + > > > > > + if (!(dev->vduse_features & BIT_U64(VDUSE_F_QUEUE_READY))) > > > > > + return; > > > > > + > > > > > + msg.req.type = VDUSE_SET_VQ_READY; > > > > > + msg.req.vq_ready.num = idx; > > > > > + msg.req.vq_ready.ready = !!ready; > > > > > + > > > > > + r = vduse_dev_msg_sync(dev, &msg); > > > > > + > > > > > + if (r < 0) { > > > > > + dev_dbg(&vdpa->dev, "device refuses to set vq %u > > > > > ready %u", > > > > > + idx, ready); > > > > > + > > > > > + /* We can't do better than break the device in this > > > > > case */ > > > > > > > > It's better to explain why we can't depend on vduse_dev_msg_sync() here. > > > > > > > > For example it did: > > > > > > > > if (unlikely(dev->broken)) > > > > return -EIO; > > > > > > > > init_waitqueue_head(&msg->waitq); > > > > spin_lock(&dev->msg_lock); > > > > if (unlikely(dev->broken)) { > > > > spin_unlock(&dev->msg_lock); > > > > return -EIO; > > > > } > > > > > > > > and > > > > > > > > if (!msg->completed) { > > > > list_del(&msg->list); > > > > msg->resp.result = VDUSE_REQ_RESULT_FAILED; > > > > /* Mark the device as malfunction when there is a > > > > timeout */ > > > > if (!ret) > > > > vduse_dev_broken(dev); > > > > } > > > > > > > > > > I'm not sure I follow you here. > > > > > > We can't do better than breaking the device because the function > > > returns no error state, and the caller does not expect an error code. > > > Do you mean we can't depend on vduse_dev_msg_sync to call > > > vduse_dev_broken(dev) by itself? > > > > I think I meant, reset seems to be more heavyweight than suspend. > > > > So if reset can fail, I don't see reason ot break device only for > > suspend failure. > > > > Sorry I still don't get you. > > This series does not implement suspend at all. It doesn't modify the > VDUSE device reset or the virtio reset behavior. It only implements > the vq ready message for the device. If the device returns an error > from that operation, what is your proposal for when the driver sends > new messages like resume? >
Friendly ping.
